City Scientists Prepare For Round 2 Of Tests On India’s Only AIDS Vaccine

While experts across the world have currently gathered at Vienna for a global conference to discuss prevention and management of HIV/AIDS, scientists from two major Indian institutes – Tuberculosis Research Centre (TRC), Chennai and National AIDS Research Institute (NARI), Pune – are clocking the successful progress of the indigenous AIDS vaccine trial. With no adverse reactions reported so far, the first phase of the trial is set for completion this year before the second phase rolls out in early 2011.

The scientists are eagerly waiting to see how the vaccine, now with a new component, will boost the immunity of 32 healthy volunteers in a low–risk group. A 2008 trial at TRC had proved to be equally safe, but the immunity boosting capacity had not met the desired requirement. Once the strength of the vaccine is established in the current round, the trial will move on to the second phase which involves a larger group of volunteers for three years, and then on to the third phase where the vaccine would also be tested on a high–risk segment.

The 18–month trial began in 2009 with 16 volunteers in each centre. The groups were further divided into two for a ‘double blind’ study. While one group was given injections thrice, the other was given injections four times. One of this was a placebo, the other the vaccine. Neither the volunteers nor the scientists knew which group received the vaccine.

Lessons from the earlier round of clinical trials carried out by TRC in August 2008 have come handy this time. “It was significant because the vaccine passed the safety test. Yet, it was not as strong as we expected it to be,” said study’s principal investigator Dr V R Ramanathan, senior deputy director, TRC. The scientists then evolved a strategy to boost the immune response and added another vaccine candidate called the DNA vaccine, which was tried by scientists in the USA. “We hope this combination will yield better results. All the volunteers received the injections in the first six months. They were asked to come on the 9th, 12th and 18th month for follow–up. We have completed the 12th month follow–up. So far, we have not seen any toxic reactions,” said NARI director Dr RS Paranjape. “The last visit for follow–up will be in December. We will then ‘unblind’ the study and the results will be available by February,” he added.

Scientists admit that it would take a long time and a lot of testing before the vaccine can be considered for use. “Phase 2 is only a larger study with a sample size that may extend up to 500. This will take at least three years. The vaccine will then be upgraded for the next level of trial, where volunteers from high–risk groups will also participate. This is where we would know if the vaccine is really efficient in stopping the virus from entering the body,” said Dr Ramanathan.
Of the 33.4 million people living with HIV/AIDS in the world, 2.7 million are in India. Though the prevalence in India is less than 0.3%, 1.7 lakh fresh cases being reported every year remains a matter of concern.

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